It must have seemed the height of folly at the time, but the fate of Ireland would be altered forever due to a plane flight over Scotland on which Sinn Fein leader Martin McGuinness and Democratic Unionist Party (DUP) chief Ian Paisley essentially ended a century of hostilities between IRA and nationalist Irish forces versus Northern Ireland contingencies still loyal to Great Britain.

By the time their plane touched down, the groundwork had essentially been laid for 1998’s Good Friday Agreement, putting to rest “The Troubles” that had claimed thousands of lives over several bloody decades.

A fictionalized account of the men’s history-making travels is the basis for the new film “The Journey,” opening Friday in the District. Timothy Spall (“Harry Potter,” “Denial”) portrays U.K. loyalist Paisley to Colm Meaney’s (“Star Trek: The Next Generation”) take on Sinn Fein leader McGuinness, who, in real life, had also been in the IRA.

“They were both very divisive figures. That I think is what makes the movie work [as] both characters could be seem to be unpalatable,” Nick Hamm, director of “The Journey,” told The Washington Times.

Mr. Hamm, a Belfast native and alum of the Royal Shakespeare Company, said that he and screenwriter Colin Bateman fashioned a fiction in which McGuinness and Paisley would be forced to share a car ride to the airport. While their chat on the airplane is a matter of public record, the fantasy of the two enemies sharing such a car ride allowed for poetic, dramatic license.

“We took it out of the plane because it wasn’t so dramatic. It’s not cinematic, as it were,” Mr. Hamm said of the enclosed space. “We fictionalized the dialogue based on their relationship over the following 10 years. The movie is the odd couple in the back of a car.”

The car ride scenes of “The Journey” almost have the feel of watching a play, which is perhaps not surprising given Mr. Hamm’s history in the theater. However, the filmmaker believed strongly in “opening up the movie in a cinematic way.” Thus, Mr. Bateman’s screenplay threw in occasional misadventures on their ride to the airport that had them stop at a church, a gravesite and even a cemetery.

“You had these set piece scenes that took the movie away from the car, which … allowed the audience to sort of breathe a little bit,” Mr. Hamm said, adding that “The Journey” was shot entirely in Ireland despite the action taking place in Scotland. “You just wouldn’t know [it’s] the same countryside almost, just separated by a little bit of sea.”

Mr. Hamm said the film has played well both in the Republic of Ireland, predominantly Catholic, and in Northern Ireland, with its Protestantism and Anglican traditions.

“When we did the premiere, both sides came to the event,” Mr. Hamm said of showing the film in Belfast, and which was attended by senior members of Sinn Fein and of the DUP, as well as members of the the Paisley family and even former members of the IRA.

“When we did the premiere in the middle of Belfast, these people were recognizing something that had actually happened,” Mr. Hamm said. “They had achieved peace and, therefore, this needed celebrating.”

However, the filmmaker cautions that even though the Good Friday Agreement did come to pass, the old angers simmer still, and the potential for a breakdown in the fragile accord is always a concern.

As is the ignorance of those who weren’t there the first time around.

“There’s a new generation in Ireland that doesn’t know what The Troubles were,” Mr. Hamm said. “What everyone’s fear is that there’s no politician right now qualified enough to reach across the divide and keep the peace process on track.

“There is a definite void,” he said, which will be aggravated by the ongoing Brexit negotiations. “It’s especially mixed up now because of the DUP supporting the Tory government.”

(British Prime Minister Teresa May is a Tory, another name for a member of the Conservative party.)

While Mr. Hamm believes British audiences may be “too close” to the material — as well as recent memories of IRA bombings in and around London even in the 1990s — he said that Irish as well as international audiences are embracing “The Journey.”

“In Ireland, there was a very emotional reaction because you’re celebrating something that they’ve achieved,” Mr. Hamm said. “And this relationship between these two guys is a unique political relationship that needs to be celebrated.

“You’re seeing two men that reached beyond their base, their own constituencies, and did something quite brave,” Mr. Hamm said of McGuinness and Paisley’s uniquely successful relationship. “I think the film speaks to a situation in which you are celebrating the art of compromise and concession.”

“The Journey” opens Friday at the District’s Landmark West End Cinema.